1. Field of the Invention
This invention relates to a method of treating nail fungus and more particularly to a method of utilizing a therapeutic polyurea composition by topical administration thereof to the affected nail.
2. Description of the Prior Art
Humans and animals alike are commonly plagued by the infiltration of micro-organisms beneath the nail, claw or hoof which result in a disease condition causing pain, discoloration, and frequently loss of the unguis. In humans, for example, some diseases which attack the nail or nail bed can be treated fairly successfully with the use of cleansing and/or antiseptic preparations, while other diseases require treatment by such means as systemic drug therapy. Nonetheless, many disease conditions of the nail, particularly onychomycosis (i.e., fungal diseases), have had a relatively low success rate for treatment due to the intransigent nature of the infectious micro-organisms.
It has been estimated that greater than twenty percent (20%) of the population of the United States over the age of 40 suffers from onychomycosis of the fingernails or toenails. The disease is known to occur to a lesser extent in people below the age of forty, but the occurrence of disease is still significant. Unfortunately, the current modalities for treatment of onychomycosis show a very low success rate.
Mycoses of the nails (onychomycoses) are intractable types of disease which have hitherto not been possible to treat satisfactorily. The term onychomycoses embraces various types of mycoses of the nails, of which those caused by dermatophytes are the most difficult to treat, whereas the mycoses of the nails caused by yeast-like fungi have hitherto been those which it has been possible most readily to treat successfully.
The difficulty with onychomycoses caused by dematophytes is additionally that they make a considerable contribution to the spread of infectious fungi. Various routes have been followed hitherto for their treatment, but without permanent success.
Common means of treating microbial diseases, including onychomycosis, include oral administration of drugs and laser therapy. Laser therapy, as yet, is not well-developed nor widely practiced, and is very expensive because it must be conducted in a doctor""s office by a trained technician. Systematic drug therapy through oral administration has also proven to be relatively unsuccessful because of drug intolerances, the expense of the medications and low patient compliance. Typically, systemic oral treatment with antifungal agents requires long term treatment with a potential for toxic side effects.
A common means of treating onychomycosis is to remove the nail completely and topically apply medication to the underlying nail bed. However, not only is such treatment cosmetically unsightly, but the fungus which invades the nail often remains in the matrix of the finger or toe (where the nail is formed) and the disease reoccurs immediately upon, or during ingrowth of the new nail. Moreover, because of the aggressive nature of this treatment, the regrown nails are often deformed in shape.
A conservative method comprises topical treatment of the nails with specific substances having antimycotic activity. A very wide variety of treatment methods has been tried for this. Thus, in a combined treatment, the nails have initially been treated with solutions of the substances having antimycotic activity, and cream dressings have been applied each night. This treatment method is by its nature also very unpleasant for, and a psychological strain on, the patient. On the one hand, the nails have to be treated with a solution several times a day. On the other hand they have to be provided with dressings, particularly at night. Furthermore, it is necessary for the diseased nails to be filed or scraped down continually, which not only is troublesome but also contributes to spreading the pathogens. The results of all this are that many of the patients do not persist with the treatment, which usually takes several months; on the contrary, they become discouraged and negligent, and thus the therapy is unsuccessful. Also detrimental to the success of treatment by this method is that the solutions and creams are usually miscible with water or hydrophilic and thus can be removed again from the surface of the nail or dissolved out of the nail on washing, bathing and showering, and thus may need to be reapplied thereafter.
Undoubtedly, treatment of diseases involving nails would be greatly enhanced by the ability to access the area around and below the nail, as well as to penetrate the nail itself, without having to remove the nail. However, the thick and/or hardened nature of nails renders access through, and to the areas below, the nail very difficult. The same can be said of diseases involving the claws or hooves of animals.
The usefulness of antifungal drugs in treating onychomycosis has been limited heretofore because of resistance to penetration of the nail or because of limited access to the nail bed through the nail. Thus, it would be an improvement in the art to provide means for enhancing penetration of the nail so that treatment of the nail with medication may occur at the situs and without having to remove or otherwise significantly damage the nail. It would also be advantageous to provide such penetration means at a reasonable cost to the consumer, and in a form which would facilitate and encourage proper and consistent self-use by the afflicted person.
This invention relates to a method of treating a nail fungus and, more particularly, to a method utilizing a therapeutic polyurea composition by topical administration thereof to the affected nail.
The method comprises applying a therapeutic polyurea composition selected from (a) a reaction mixture comprising a first component of an oligomeric amino benzoic acid ester or amide having the formula 
where n is an integer from 2 to 4; each x is one or two; each benzoyl nucleus is para, meta, or di meta amino-substituted; each Z is xe2x80x94Oxe2x80x94 or xe2x80x94Nxe2x80x94; and G is an n-valent radical obtained by removal of hydroxy groups or amino groups from an n-valent polyol or polyamine having a molecular weight of from about 400 to about 6,000; and a second component comprising a polyisocyanate; (b) a stabilized reaction mixture comprising the first component of the oligomeric amino benzoic acid ester or amide of formula I, combined with the second component of the polyisocyanate in a stabilizing carrier; (c) a blocked reaction mixture, comprising the first component of formula I having at least one of its aromatic amino groups blocked by a reaction with an aldehyde, combined with the second component, polyisocyanate; and (d) a mixture of any the foregoing.